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EXCLUSIVE: Seven former North County landfills leaking contaminants

Seven former North County dumps are leaking contaminants intosurrounding groundwater as the decomposing remains of decades’worth of waste seep out of the unlined soil beds, water officialssaid in a series of recent interviews.

However, water quality officials said they know of no drinkingwater supplies in North County that have been contaminated bylandfills.

Because most residents receive piped water through the San DiegoCounty Water Authority, “the risk to most county residents is verysmall or negligible, while local water supplies located in morerural areas may be at a somewhat elevated but unquantified level ofrisk,” said John R. Odermatt, a senior engineering geologist forthe California Regional Water Quality Control Board’s San Diegoregion.

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Since the seven landfills ---- in Bonsall, Valley Center, Poway,San Marcos, Oceanside and Carlsbad ---- closed more than a decadeago, an airport, parks, schools and homes have been built on ornear the sites.

Officials said that while the former landfills are leachingchemicals known to cause cancer, reproductive harm and other healthproblems, all seven sites are tested regularly and the regionalwater board has ordered corrective measures to stop the seepage.Measures to extract hazardous gas and liquid from the sites havekept the contamination from spreading, they said.

However, as county Supervisor Bill Horn and other officials pushfor more reliance on groundwater sources as a hedge against limitedwater supplies, safe groundwater has become a pressing concern. Andplans to build the Gregory Canyon Landfill on county land near thePala Indian Reservation outside Fallbrook have focused attention onthe long-term storage of trash, officials said.

A toxic mix

The landfills, built between the late 1940s and 1970s, precededenvironmental rules that govern waste disposal today, and served ascatch-all basins for a mix of routine trash and toxicchemicals.

“The hazardous-waste checks didn’t start until the 1990s,” saidMichele Stress, a unit manager for the county Department of PublicWorks, which monitors and maintains the seven sites.

Residents and businesses are now required to discard hazardousmaterials at special sites, but landfills built before the ‘90stook in everything from yard clippings and food scraps to paintthinner, batteries, solvents, motor oil and dry-cleaningchemicals.

“Probably Jimmy Hoffa is buried in one of those things,producing methane,” said Henry Cole, a Maryland-based environmentalconsultant, referring to the powerful Teamsters Union leader whodisappeared under mysterious circumstances July 30, 1975.

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Landfills that opened before the ‘90s also lacked bottom linersthat modern landfills employ to keep pollution from seepingoff-site.

“A lot of companies and businesses, big and small, in thepost-World War II era up into the 1970s and 1980s routinely threwaway really nasty stuff in landfills,” said Jonathan Scott, aspokesman for Clean Water Action, a national environmentalorganization. “All landfills eventually leak over time, even modernones with state-of-the-art liners and collection systems.

“But the older ones are really problematic because they don’thave (liners), and because the stuff that went into them can bepresumed to be really bad.”

Stress said, however, that North County had little heavyindustry during that period, so landfill contents likely containmore agricultural scraps than industrial waste.

Nonetheless, the brew of chemicals in the seven landfills isreleasing methane gas from decomposing biological waste, along withvolatile organic compounds ---- synthetic chemicals that evaporateeasily and can pollute air and water supplies.

Recent monitoring tests at the former landfill sites in Powayand Bonsall and at McClellan-Palomar Airport in Carlsbad andBradley Park in San Marcos showed that some pollutant levelsexceeded state health limits.

All seven landfills have registered some leaks of contaminants,however, and officials said that because those chemicals don’toccur naturally, any leak exceeds standards set for thosesites.

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“Any volatile (organic compound) that’s detected in groundwateris an indication of release from the landfills, which is aviolation of their current discharge requirements,” said CherylProwell, a water resource control engineer for the regional waterquality board.

Dealing with the dumps

As the dumps filled up from the late 1960s through the 1980s,the county covered them and found other uses for the sites.

Jefferson High School, Clair Bergener School and MissionElementary School surround the former Mission Avenue landfill inOceanside, water board documents show.

Bradley Park sits over a former county landfill in San Marcos,the Aerie Park equestrian facility operates on the site of theformer Valley Center landfill, and Palomar Airport sits atop theformer landfill in Carlsbad.

Rural homes and orchards have sprung up near the former Bonsalllandfill, the San Elijo Hills neighborhood abuts the former SanMarcos landfill, and homes surround the former Poway landfill, nearthe section of Poway Road between Espola Road and Highway 67 knownas the Poway Grade.

In some instances, contaminated materials have risen to thesurface.

A water board report on the Mission Avenue landfill in Oceansidenoted that in 1978, the year the dump closed, there was not enoughsoil cover to prevent water from percolating through the waste. Thereport also noted that the closed landfill lacked erosion controland was polluting the San Luis Rey River.

“Bad smelling, dark leachate was flowing from several points inthe landfill and mixing with the storm run-off flowing down thegully to the river,” the report stated. “Paper, tires, tin cans andother debris were visible at least 2,000 feet beyond the base ofthe landfill.”

In another document, the water board cited the county’s concernsin 1996 about a fireworks display at Bradley Park in San Marcos,stating that the presence of methane gas at the site posed a riskof fire and explosion hazards. That particular site has little orno gas emissions today, said Jason Forga, a senior civil engineerfor the county.

A 2004 cleanup and abatement order for the Valley Centerlandfill stated that pollution from the site was seeping into thelower San Luis Rey River and surrounding areas.

To correct those problems, county officials have installedsystems to remove contaminated water and built gas-extraction wellsthat suck methane and other harmful vapors from the landfillsbefore burning them, Stress said.

At the former San Marcos landfill near San Elijo Hills, brightyellow wildflowers and other native brush grow atop a 5-foot layerof clay soil that contains the trash. A county contractor, SCSEngineers, manages gas emissions, operating a 24-hour flare thatburns methane and volatile organic compounds before they reach theair or groundwater. Another company, Fortistar Methane Group, usesgas flares to generate power, which it sells to SDG&E.

Officials also inspect the topography above the landfills forplaces where contaminated water might be pooling, adding dirt asneeded to prevent runoff, Forga said.

The county orders monthly gas checks and conducts semiannualtests for groundwater pollution, officials said, and spends $5million a year on monitoring and maintenance of closed landfillsand burn sites countywide.

Odermatt, the water board’s senior engineering geologist, saidit’s unclear how long that will be the case, adding that the boarddoes “not speculate on how long monitoring and maintenance maycontinue.”

Leaky bathtubs

The corrective measures, including covering the top of thelandfills, help control but don’t actually contain thecontamination, county officials said.

“You have to think of the landfill as kind of a leaky bathtub,particularly where the liner’s on top,” said Cole, theMaryland-based environmental consultant. “Usually, they’re not wellconstructed. They tend to crack, they develop fissures, they geteroded. Water infiltrates constantly and picks upcontamination.”

Cole said the water pressure in landfills is usually higher thansurrounding areas, and can force contaminated water into untaintedwells. He also said that volatile chemicals can pose a problemknown as “vapor intrusion,” when chemicals evaporate fromgroundwater and contaminate the air in nearby homes.

In Bonsall, monitoring wells along the perimeter of the siteshave shown elevated levels of three chemicals, includingtetrachloroethylene, according to the water board’s cleanup andabatement order for the site.

The chemical, which can cause kidney and liver damage, and maylead to cancer or reproductive harm, has also shown up in a privateagricultural well in the area, Prowell said.

It could affect 34 other nearby wells, including seven domesticwells and a number of agriculture wells, she said.

The county has proposed improving drainage on the site to reducemoisture in the buried debris and prevent runoff.

Although officials said the threat to drinking water is low,that risk could rise if more communities tap into groundwater, asSupervisor Horn has suggested they do. In January, Horn convened apanel of water experts to talk about how the county should exploregroundwater use in order to stretch the region’s water supply inbackcountry areas.

Local water district officials said their groundwater is limitedor isolated from the former landfills. But Daniel Tartakovsky, a UCSan Diego engineering professor who sat on Horn’s water panel lastmonth, said the county has been overly conservative in itsgroundwater estimate. Without studying areas site by site,Tartakovsky said, the county may have underestimated watersources.

The long-term safety of landfills also weighs heavily on thepermitting process for the proposed Gregory Canyon Landfill outsideFallbrook. The landfill is proposed for 308 acres of undevelopedland near Pala, alongside the San Luis Rey River. The countyDepartment of Environmental Health must decide whether to issue thepermit by April 1.

At a meeting last month, speakers including Pala Band of MissionIndians Chairman Robert Smith, county Supervisor Pam Slater-Priceand other officials said the project threatens habitat, water andair quality. No landfill liner is fail-safe, they argued.

In addition to the five-layer composite liner, the company’swebsite stated, landfill plans would include a system to collectand contain landfill liquids, and a groundwater treatment plant toprotect water quality.

Odermatt said groundwater hazards posed by aging landfills haveled to greater scrutiny of new landfill design.

“That’s one reason we’ve been very critical, and are taking avery hard look at the proposed Gregory Canyon design,” he said."Because the people out there don’t get piped-in water. They getwater from wells, so we’re really looking at that hard.”

Stress, with the county Public Works Department, said the slowdecay of past trash requires ongoing attention. She said the countyexpects to manage older landfills in perpetuity.

“This monitoring is long-term,” Stress said. “It’s going to begoing on for years ---- we think forever. We’re going to be doingthis until the landfill is a dry tomb.”